Hydraulic lift attachment



Oct. 20, 1970 I A. E. LONG HYDRAULIC LIFT ATTACHMENT 5 Sheets-Sheet 1 Original Filed June 20, 1967 INVENTOR. ALBERT E. LONG ATTORNEY Oct. 20, 1970 A. E. LONG 3,534,874

HYDRAULIC LIFT ATTACHMENT Original Filed June 20, 1967 5 Sheets-Sheet 2 emf v ATTORNEY Oct. 20, 1970 T A. E. LONG 3,534,874

HYDRAULIC LIFT ATTACHMENT Original Filed June 20, 1967 I 5 Sheets-Sheet 5 INVENTOR. ALBERT E. LONG ATTORNEY 0a. 20, 1970 A. E. LONG 3,534,874

HYDRAULIC LIFT ATTACHMENT Original Filed June 20, 1967 5 Sheets-Sheet 4 INVEN TOR LBERT E. L NG ATTORNEY A. E. LONG HYDRAULIC LIFT ATTACHMENT Oct. 20, 1970 5 Sheets-Sheet 5 Original Filed June 20,

H l l i hd INVENTOR. ALBERT E. LONG ATTOR NE Y United States Patent 3,534,874 HYDRAULIC LIFT ATTACHMENT Albert E. Long, 3832 Highland Ave., Shadyside, Ohio 43947 Continuation of application Ser. No. 647,379, June 20, 1967. This application Sept. 3, 1969, Ser. No. 855,052 Int. Cl. B60p 1/48, 1/44; B66c 23/44 US. Cl. 214-77 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a hydraulic lift attachment for trucks or for loading docks. The lift is supported and raised by a chain and sprocket means and is powered by a fluid cylinder which exerts a thrust against a lever means attached to the chain. The device has several important modifications which can convert it to a portable lift unit, to a crane assembly or to an odd-shaped materials loading apparatus.

This application is a streamlined continuation of application Ser. No. 647,379 filed June 20, 1967.

BACKGROUND OF THE INVENTION In the past, hydraulic lift attachments for trucks have been heavy and expensive; heavy in order to support and to lift the loaded platforms to the level of the vehicle; expensive because of costly installation and of the structural and power requirements of these heavier lift attachments.

Another disadvantage of conventional lifts is that they are designed for use on a single, specific truck and cannot be readily adapted for use on other trucks, nor can they be used with loading docks which are higher than the load-bed of the truck.

SUMMARY OF THE INVENTION An object of the present invention is to obviate the above-named disadvantages by providing a lift which is compact and inexpensiveyet sturdy and powerful enough to support and to lift heavy loads.

Another object of the invention is to provide a portable lift attachment which is quickly and easily attached by one person to any size truck bed, loading platform, work bench or the like and to provide a lift whose height may be adjusted to a Wide range of elevations and whose platform may be tilted to any angle through 180 from a vertical position.

Still another object of the invention is to provide a lift which can be adapted to load pipe, logs, cans or the like.

A further object of the invention is to provide a lift which can be adapted to be used as a crane or towing rig.

Other objects and advantages will become apparent from a study of the following description when taken with the accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a perspective view of a lift attachment embodying the present invention;

FIG. 1B is a perspective view of a supporting assembly thereof with the lift platform shown in dotted outline for clarity;

FIG. 2A is a perspective view thereof with the lift in a locked vertical position;

FIG. 2B is a side view thereof with the lift in a lowered vertical position;

FIG. 3 is an enlarged fragmentary view of an anchoring assembly shown in FIG 1A;

FIGS. 4 and 5 are perspective views of the lift in different operational positions;

FIG. 6 is a perspective view of a modification of the invention showing a crane attachment; FIFIG6. 6A is a fragmentary view of a support means in FIG. 7A is a perspective view of a housing unit containing the lift as shown in FIG. 1A;

FIG. 7B is a side elevational view of the housing unit in FIG. 7 adjacent to a loading dock;

FIG. 7C is an enlarged fragmentary view of the ramp means shown in FIG. 7A; and

FIG. 8 is a perspective view of a modification of the invention showing a hook means for loading pipe, barrels, tires or the like.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to FIG. 1A of the drawing, a triangular fixed frame assembly, generally denoted by numeral 4, is bolted to the underside of a truck or trailer (shown in dotted outline) in a manner which will be subsequently described.

A support gate or frame 5 is pivotally attached along one side to fixed frame assembly 4. Support arm 6 is also attached to the assembly and is substantially parallel with the adjacent sides of gate 5. Lock nuts 7 on arm 6 can be adjusted to shorten or lengthen the arm to effect tilting and leveling of the supported platform 14 to be described hereinafter.

A chain 11 has one end fixed to a portion of gate 5. The chain 11 is guided over a sprocket wheel mounted on assembly 4 and a sprocket wheel 8a rotatably mounted on lever plate 8. The other end of the chain is attached to crossbar 19 of bolt brace 19. The chain supports the weight of the lift as well as lifting and lowering the lift.

The sprocket wheel 8a is rotatably mounted on one leg 8b of a lever plate 8, the other leg of which is pivotally mounted on fixed frame assembly 4. A hydraulic cylinder 9 is attached at 8c to the neck portion of lever plate 8. The other end of cylinder 9 is mounted on a shaft at the lower portion of bolt brace 19.

As seen in FIG. 1B, a support assembly of platform 14, shown in dot and dash autline, is comprised of a pair of parallel arms 20, and a pair of support braces 23 pivotally attached to clevis 22 of arms 6 and 6a and joined near the free end of its platform 14 by crossbar 25 through slides 24 mounted on arms 20. Braces 23 are pivotally mounted to support clevis 22 and in sliding relationship with arms 20 by means of hinged support bar 21. Arms 20 are pivotally attached by bolts to an extension 5a of gate 5. Bracket or stop element 24 on arms 20 limits the extent to which support arms 23 may move in relationship to arms 20. The mechanical arrangement of this support assembly provides substantial and optimum truss support for the load-bearing platform 14 without excessive bulk or weight.

A pair of locking bolts 18 are spring loaded and positioned so as to lock arm 23 with extension 5a to produce a continuous rigid arm. The bolts 18 can be used to lock the platform at a preselected angle, if desired.

A locking bar 26 is pivotally mounted on crossbar 25. Clamp 28 secures the loose end of bar 26 when the lift is in operation, A forked clamp lock 27 on arm 20 receives locking bar 26 to lock the entire support assembly in a vertical, tailgate position (best seen in FIG. 2A).

Platform 14 (shown in dotted outline in FIG. 1B) is supported by chain 11 and the support assembly. The leveling of the platform 14 is made possible by means of making arm 6 longer or shorter through the use of lock nuts 7 abutting against sleeve 6a.

Hydraulic cylinder 9 is operated by means of a power pack 10 which is mounted on bracket 30 (FIG. 2A) of the fixed frame assembly. Lever 29, which rides between the hinged top part of 30, is secured permanently to the axle of the hinge which in turn, is connected to the control lever of the power pack. Handle 33 is secured to lever bar 31 by a set screw for shortening or lengthening of the handle distance. Bar 31 slides through support arm 32 welded to bracket 30.

The entire lift attachment can be mounted on the undercarriage of a truck or trailer by the following means. The back portion of the triangular fixed frame assembly 4 is bolted on the undercarriage of the vehicle (as shown in FIG. 1A). A Z-plate 13 is positioned against the edge of the load-bed and the lift attachment is securely bolted to the load-bed and to the Z-plate with bolts 16 and 1612 (which pass through slotted holes in support plate 15 of the assembly).

Square tube 1, supporting bolt clamp 3A, telescopically slides on channel support 12 where it can be selectively locked into position with set screw 3C to fit various distances of under truck-bed cross members. When the desired position has been located, bolt clamp 3A is then used to raise or lower the support bar 12 to level off the entire fixed frame assembly anchored at the back portion of the lift. When the assembly is level, welded roundwasher 3D rests on the bottom of a truck cross member. The square forked washer 3F is placed directly under the cross member and tightened upwardly by lock washer and nut 3, thus securing the fixture to the cross member using the round washer 3D as a stop. Tongues of the square washer 3F are bent upwardly behind the cross member to prevent the locking fixture from slipping.

In the case where it is not possible or not desirable to drill holes in the load-bed, the entire lift attachment may be mounted without the use of sunken bolts 16B by substituting common bolts 16 for bolts 16B. Bolts 17 screw securely against the underside of the load-bed through plate 15 as a stabilizer to keep the lift from movmg.

In operation, platform 14 must be upright to be unlocked or locked. To unlock the platform (see FIG. 2A), lock bar 26 is released and swung up to crossbar 25 where it is clamped. Lock bolts 18 are released, and platform 14 is lowered. Elements a, 21, 22, 23 and 25 then become movable. As the platform is lowered, the lower part of hinged support bar 21 for clevis 22 of arm 6 shifts forwardly, bringing out with it from the platform, the support arm 6. This action causes brace 23 to move forwardly to the front of the platform on crossbar 25, supported by arms 20, and secured in brackets 24. When crossbar 25 is stopped by brackets 24, the platform will then be level and ready to lower by pushing handle 33 on power pack inwardly.

Looking at the mechanism when lowered, clevis arm 22 of arm 6 has shifted away from the locking bolt 18 and the bolt hole on brace 23. Crossbar 25 is resting against the front of bracket 24 where it supports the middle of the platform load. Locking device 26 for keeping the platform upright is shown clamped to crossbar 25. Extension 5a of gate 5 has not moved and remains as the back support of platform 14.

Platform 14 can now be lowered by pushing handle 33 to release the hydraulic pressure in cylinder 9 and allow the plateform to descend, in a level position, by gravity (see FIG. 4). After loading (or unloading) the platform may be raised to the level of the truck load-bed by pulling on handle 33 which activates power pack 10. The power pack supplies fluid under pressure to the cylinder 9 which, in turn, exerts a thrust against the neck of lever plate 8. This forces the lever plate to rotate downwardly and exerts a substantial pull of the movable sprocket 8a and on chain 11. By means of this pull, chain 11 lifts support gate 5 and supported platform 14. Because of the position of the cylinder with respect to the lever late, maximum thrust is exerted when the platform is on the ground and when the intertial forces of the platform in this position require the greatest compensating force to begin the lift.

A modification of the invention that transforms the attachment into a towing device is seen in FIGS. 6 and 6A. All the platform assembly shown in FIG. 1A and FIG. 1B is removed, including arms 6 and support gate 5. Chain 11 and the sprocket wheels are also removed and replaced by pulleys and steel cable.

A crane support 41 is the main support element and is made of heavy walled steel pipe or similar material. Axle bar or hinged support 42 extends back into pipe 42B and is anchored by a setscrew, Threaded to crane support 41 is pipe clevis 42A which fits over axle rod 42 and is fastened by a cotter pin. Pipe 42B is bolted to plate 15 of the fixed frame assembly. Plate 43 supports pulley 44 and cable clevis 20 and is bolted to bolt brace 19. Crossbars 47, welded to upright pipe members of support 41, have an inside bar 48 that acts as an axle for pulleys and can be slid to one side if the pulleys are to be replaced. Inside bar 48 in anchored by set screws or cotter pins.

Pipe 49 is a guide for cable 58 and is attached by arms 49A to crossbars 47. Cable 58 go s through all guides to the top of the crane where it entrains over pulley 57 at the tapered end of the crane support and then drops to support hook 51. Cable 58 passes around the pulley of hook 51 and up to cross member 50 where it 15 secured by cable clevis. Clevis arms 50A ride as a hinge on steel axle bar 50B through cross member 50. Cable 58 runs between clevis arms 50A.

The crane support attachment is raised or lowered into position by winch 52 which is bolted to the truck loadbed. Lock arm 52A is welded to a crank base and moves with the crank around holes 52B. To stop movement, a spring lock-pin 52C is released and the lock-pin drops mto any hole 52B.

In another modification the hydraulic lift assembly may be attached to a loading dock as seen in FIG. 7A. This arrangement is especially useful Where the dock is too high to service low bed trucks. The lift, generally denoted by numeral 34, is mounted in an open front, boxlike construction 31. The top portion 33 is fastened to the underside of the loading dock. Since this housing unit will have a set floor thickness, adjusting parts to raise or lower the height of the lift, such as the Z-plate and sliding device 1 can be eliminated.

The lift can be bolted to the steel cross members supporting the dock, through the holes in plate 15. At the front end of the lift, channel supporting bars 12 can be drilled at various distances to coincide with the underdeck cross members, and then bolted in place. Revolving caster wheels 37 fixed to the under part of the housing unit make this a portable, push-ground device to service different areas of the docking platform where this device is used. These wheels are supported by channel H beams. A sliding rail affixed to the top of these beams 37A consists of a modified channel T beam, and when these T beams are pulled forwardly, they act as a support leg to prevent the loader from tipping while in operation. A screw bolt 37B attached at the end of this T beam extends down through the beam to the ground. The bolt acts as an anchor or stabilizer and can be adjusted by screwing up or down to get proper support against tipping.

As seen in FIG. 7C, a flexible ramp 32 consists of three plates hinged together, the length of which are the same as the width of the housing deck 33. One side-plate 32A is bolted to the top of the housing unit. The middle plate 32B forms a ramp to reach up or down to the top of the housing deck. The other side-plate 32C lays on top of the edge of the loading dock where it is secured by pins 32D.

A further modification (as seen in FIG. 8) embodies a hook attachment, generally denoted by numeral 60, for loading cylindrical or odd-shaped objects such as logs, tires, pipe, cans or the like. Platform 14 and support arms 6 are removed from the lift assembly before attaching the hook attachment.

Hook attachment 60 is pivotally mounted on gate 67 which corresponds to gate in FIG. 1A. Hook attachment '60 is comprised of a pair of fork-like hooks 62 stabilized by cross bars 65. The hooks curve downwardly at the outer end 61 so as to facilitate the loading of objects from ground level. Firm support is given the hooks by a welded bar or stop 66 resting under support gate 67. If materials smaller than the distance between the hooks are to be loaded, a deck covering 68 made of steel panels or other suitable material may be attached to the top edge of the hook attachment.

In operation, the hook is lowered until the outer end 61 rests on the ground to receive the objects to be loaded. After loading, the hook attachment is raised to slightly above the level of the truck load-bed by chain 11, as described in connection with FIG. 1a, thus allowing the loaded material to roll or slide onto the truck load-bed. The hook attachment has the added feature of being able to rest, out of the way, on the truck bed 64 when not in use (as shown in dotted outline in FIG. 8).

Thus it can be seen that I have invented a novel hydraulic attachment which is efiicient, compact, inexpensive, portable and highly versatile. In addition, I have provided modifications to the invention so that the lift may be used as a towing rig, it can be housed for use as a portable loading dock device, or as an apparatus for loading logs, barrels, pipe or the like.

I claim:

1. A hydraulic tail gate lift attachment for mounting underneath the load bed of a vehicle, said load bed having a transversely and horizontally extending rear edge, comprising a fixed frame assembly having a front portion including first fastening means for detachable fastening and suspending said assembly from a cross frame extending transversely and located underneath the load bed of the vehicle and having a rear portion including suspending means extending transversely of said vehicle and supported by attachment over a substantiallength of said horizontal, transversely extending rear edge of said load bed, and second fastening means suspended from said suspending means for fastening to said rear portion of said frame assembly, means for vertically adjusting at least one of said fastening means so as to level the top portion of said fixed frame assembly, a support assembly pivotally mounted on the lower rear portion of said fixed frame assembly, power amplifying means for tiltably raising and lowering said support assembly, and a platform supported on said support assembly.

2. A hydraulic tail gate lift attachment as recited in claim 1 wherein said top portion of said fixed frame assembly includes telescoping frame means extending longitudinally of said vehicle for selectively adjusting the length of said top portion and the distance between said respective fastening means to enable mounting of said attachment to different vehicles having different spacings between a cross frame and the rear edge of the load bed.

3. A hydraulic tail gate lift attachment as recited in claim 1 wherein said power amplifying means includes chain means having one end anchored to said fixed frame assembly and the other end anchored to said support assembly for tiltably raising and lowering said support assembly, and hydraulic means mounted in said fixed frame assembly for effecting movement of said support assembly in opposite directions so as to selectively lift or lower said platform.

4. A hydraulic tail gate lift attachment as recited in claim 3 wherein said support assembly includes bracing means for giving truss support to the middle portion of said platform, said bracing means comprising a pair of support arms pivotally attached to said fixed frame assembly, a pair of locked nuts on said arms to selectively adjust the length of said arms, a pair of support braces and a pair of hinged support bars pivotally mounted on the end of said arms, a crossbar mounted on the other end of said support braces which moves in slidable relation to said support assembly, and a bracket attached to said support assembly which retains and limits the slide of said crossbar.

5. A hydraulic tail gate lift attachment for mounting underneath a vehicle, comprising a fixed frame assembly suspended underneath the vehicle load bed, a support frame pivotally mounted on the lower portion of said fixed frame assembly, chain means having one end anchored to said fixed frame assembly and having the other end portion anchored to said support frame for tiltably raising and lowering said support frame, lever means pivotally mounted on said fixed frame assembly, said chain means being looped about a sprocket wheel mounted on said lever means, and hydraulic means for selectively tilting said lever means in opposite directions so as to selectively lift or lower said support frame through said chain means, one end of said hydraulic means being connected to the rear portion of said fixed frame assembly, the other end of said hydraulic means including a piston so connected to said lever means relative to said sprocket wheel that relatively small movement of said piston will affect relatively large movements of said support frame, and a tail gate platform mounted on the free end of said support frame.

6. A hydraulic tail gate lift attachment as recited in claim 5 wherein said lever means is of substantially triangular outline, one corner of which is pivoted to said fixed frame assembly, another corner pivoted to the other end of said hydraulic means which includes a piston and cylinder, and the third corner having mounted thereon a sprocket wheel about which one end portion of said chain means is looped with an extremity thereof attached to said fixed frame assembly so that a relatively small movement between said hydraulic cylinder and piston will effect a comparatively large lifting or lowering movement of said support frame. I

7. A hydraulic tail gate lift attachment as recited in claim 5 wherein said support frame includes a parallelogram linkage having an end portion secured underneath and adjacent the free end portion of said support frame to provide assured support for heavy loading, and a substantially horizontal lift platform mounted on the free end of said support frame.

8. A hydraulic tail gate lift attachment as recited in claim 5 wherein said fixed frame assembly has a front portion including fastening means for detachably fastening said assembly to a cross frame underneath the load bed of the vehicle and having a rear portion including fastening means for attachment to the rear edge portion of the load bed.

9. A hydraulic tail gate lift attachment as recited in claim 1 wherein said suspending means comprises a Z- plate suspended by the rear edge of said load bed, and wherein said corresponding fastening means is suspended by the lowermost horizontal flange of said Z-plate and is adjustable to enable adjustment of the distance between said rear edge of said load bed and said rear portion of said fixed frame assembly.

10. A hydraulic tail gate lift attachment as recited in claim 2 wherein said first fastening means includes ad- 3,534,874 7 8 justing means for adjusting the vertical distance between 3,175,706 3/ 1965 Mathers et a1. said fixed frame assembly front portion and said cross 3,332,562 7/1967 Kokott. frame.

References Cited GERALD M. FORLENZA, Primary Examiner UNITED STATES PATENTS 5 R. J. SPAR, Assistant Examiner 2,542,047 2/1951 Mullin. US. Cl. X.R.

2,822,938 2/1958 Ormsby. 21486,130 

